Obstructive sleep apnea (OSA) syndrome occurs with an estimated prevalence of 2-9% in adult American population with an increasing incidence (Strollo et al. 1996; Shamsuzzaman et al. 2003). OSA has been recognized as a major cause of morbidity in recent years. The condition is firmly seated within a spectrum of sleep-related breathing disorders (Flemons 2002), including snoring, upper airway resistance syndrome and obesity-hypoventilation syndrome. Left untreated, OSA can manifest in conditions with significant detriment to quality of life: daytime sleepiness (Johns 1993) and cognitive impairment (Findley et al. 1986). More significantly untreated OSA leads to increased morbidity and mortality from systemic and pulmonary hypertension (Marin et al. 2005), myocardial infarction (Hung et al. 1993), cardiac arrhythmias (Guilleminault et al. 1983), stroke and an increased risk of motor vehicle accidents (Teran-Santos et al. 1999). Given these implications, accurate and early diagnosis of OSA can potentially benefit early interventions to halt initiation and progression of cardiovascular diseases. However, due to the lack of consensus regarding specific diagnostic tools and criteria, most of the patients with OSA remain untreated and the management of complications adds to the burden of healthcare costs.
Obstructive events occur when tissue in the upper airway collapses during sleep. This occurs during the negative pressure environment of inspiration. The exact sites of collapse vary in each person depending on their anatomy and to date there is no acceptable mechanism to predict or identify site of obstruction.